I've had it happen twice on my 2012, and once on my 2013. I have read everything I can find on it including Honda's official statement which said up to 15% oil capacity could be made up of gas. ha, no thanks. Basically the fuel injector nozzle does not seat all the way closed when you shut off the bike sometimes and the gas bleeds off the pressure thru the nozzle into the intake valves and down the cylinder into the crank. It can only happen when the bike is off other wise the gas would be burnt. I don't think it is happening just on the Hondas, but it is more noticeable because the Hondas low oil volume and separate engine oil from the transmission. Anyways, I don't know what causes it just that it can happen. I don't start my bike without checking the oil for the first ride of the day.